| AUTORES | García AM, Moguilner S, Torquati K, García-Marco E, Herrera E, Muñoz E, Castillo E, Kleineschay T, Sedeño L & Ibáñez A |
|---|---|
| 2019 | |
| JOURNAL | NeuroImage |
| VOLUMEN | Volume 197, 15 August 2019, Pages 439-449 |
| ABSTRACT | Research on how the brain construes meaning during language use has prompted two conflicting accounts. According to the ‘grounded view’, word understanding involves quick reactivations of sensorimotor (embodied) experiences evoked by the stimuli, with simultaneous or later engagement of multimodal (conceptual) systems integrating information from various sensory streams. Contrariwise, for the ‘symbolic view’, this capacity depends crucially on multimodal operations, with embodied systems playing epiphenomenal roles after comprehension. To test these contradictory hypotheses, the present magnetoencephalography study assessed implicit semantic access to grammatically constrained action and non-action verbs (n = 100 per category) while measuring spatiotemporally precise signals from the primary motor cortex (M1, a core region subserving bodily movements) and the anterior temporal lobe (ATL, a putative multimodal semantic hub). Convergent evidence from sensor- and source-level analyses revealed that increased modulations for action verbs occurred earlier in M1 (∼130–190 ms) than in specific ATL hubs (∼250–410 ms). Moreover, machine-learning decoding showed that trial-by-trial classification peaks emerged faster in M1 (∼100–175 ms) than in the ATL (∼345–500 ms), with over 71% accuracy in both cases. Considering their latencies, these results challenge the ‘symbolic view’ and its implication that sensorimotor mechanisms play only secondary roles in semantic processing. Instead, our findings support the ‘grounded view’, showing that early semantic effects are critically driven by embodied reactivations and that these cannot be reduced to post-comprehension epiphenomena, even when words are individually classified. Briefly, our study offers non-trivial insights to constrain fine-grained models of language and understand how meaning unfolds in neural time. |
| En este estudio de magnetoencefalografía investigamos la coordinación temporal de dos sistemas semánticos durante el procesamiento del lenguaje. Los participantes leyeron 100 verbos de acción (como aplaudir) y 100 verbos abstractos (como desear). La actividad de la corteza motora (implicada en la realización de movimientos corporales) discriminó y clasificó los estímulos de cada categoría en una ventana temprana (∼100-190 ms), mientras que el lóbulo temporal anterior (implicado en procesos conceptuales multimodales) sólo lo hizo más tardíamente (∼250-500 ms). Estos resultados sugieren que las palabras rápidamente nos hacen “revivir” determinadas experiencias corporales y que esta simulación interna no es posterior a la activación de información conceptual integrativa. |